Video communication signals may generally utilize a modulated subcarrier to communicate video information. For example, various video communication signals may communicate video color information by phase-modulating a subcarrier signal. A receiver of such information may then extract the communicated video information by processing the phase-modulated subcarrier signal (e.g., in conjunction with a reference subcarrier signal). Such a reference subcarrier signal may, for example, be communicated directly to the receiver (e.g., as a subcarrier burst signal) or may be derived by the receiver.
In various video communication techniques, polarity of the modulated subcarrier and/or reference subcarrier may change. By way of illustration, the Phase Alternation Line (PAL) video standard includes inverting the polarity of the color signal component between adjacent scan lines. Therefore, processing such a signal may include utilizing polarity information. For example, in processing such a PAL television signal, the color synchronization process may include generating a switching signal to track PAL signal polarity changes (e.g., alternating on a line-by-line basis). Such a switching signal may, for example, be produced by processing subcarrier burst information. However, the generation of such a switching signal may be susceptible to noise. For example, noise may result in a switching signal changing state when the polarity of the subcarrier has not changed. An incorrect switching signal may then, in turn, cause incorrect processing of the modulated subcarrier, which may result in a relatively poor quality video presentation.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with the present invention as set forth in the remainder of the present application with reference to the drawings.